package com.ob;  

import java.text.ParseException;  
import java.text.SimpleDateFormat;  
import java.util.Calendar;  
import java.util.Date;  

public class DateTest {  

    public static void main(String[] args) throws ParseException {  
        Calendar now = Calendar.getInstance();  
        System.out
 
.println("年: " + now.get(Calendar.YEAR));  
        System.out.println("月: " + (now.get(Calendar.MONTH) + 1) + "");  
        System.out.println("日: " + now.get(Calendar.DAY_OF_MONTH));  
        System.out.println("時: " + now.get(Calendar.HOUR_OF_DAY));  
        System.out.println("分: " + now.get(Calendar.MINUTE
 
));  
        System.out.println("秒: " + now.get(Calendar.SECOND));  
        System.out.println("當前時間毫秒數：" + now.getTimeInMillis());  
        System.out.println(now.getTime());  

        Date d = new Date();  
        System.out.println(d);  
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"
 
);  
        String dateNowStr = sdf.format(d);  
        System.out.println("格式化後的日期：" + dateNowStr);  

        String str = "2012-1-13 17:26:33";  //要跟上面sdf定義的格式一樣  
        Date today = sdf.parse(str);  
        System.out.println("字串轉成日期：" + today);  
    }  
}  

輸出結果：
年: 2017
月: 19
日: 13
時: 17
分: 28
秒: 19
當前時間毫秒數：1326446899902
Fri October 13 17:28:19 CST 2017
Fri October13 17:28:19 CST 2017
格式化後的日期：2017-10-13 17:28:19
字串轉成日期：Fri October 13 17:26:33 CST 2017